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        검색결과 337

        123.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate the odor arising from the Cheong-ju industrial complex area for odor materials confirmation, and to predict the impact of the odor in the residential area using the CALPUFF Model. Among the odor causing substances in the area with a rising number of collective complaints due to odor, methyl sulfide, acetaldehyde, propionaldehyde, n-buthylaldehyde, n-valeraldehyde and styrene were detected. Odor causing substances detected in the area surrounding the industrial complex include ammonia, hydrogen sulfide, n-buthylaldehyde, toluene, xylene, benzene and styrene. Using the CALPUFF Model, it was predicted that 1hr average was 3.981~7.553 OU/m3 and 24hr average was 1.753~2.359 OU/m3. In terms of odor intensity, the predicted 1hr average was 0.6~0.9 and the 24hr average was 0.2~0.4.
        4,000원
        124.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this paper is to investigate the determinants of new product diffusion. We seek to document and explain systematic features of product diffusion. In this essay, we examine the well-documented empirical regularity that the speed of diffusion has accelerated during the twentieth century. The empirical results show that the main source of acceleration are faster declines in prices. Faster price declines make the product affordable to more consumers within a given period of time. Based on theories of intertemporal price discrimination and learning-by-doing, the association between the speed of adoption and the speed of price decline was explained. Faster price declines are attributed to several product characteristics as well as changes in income distribution. Above all, the introduction of consumer electronic products in more recent years can be regarded as the most important factor in accelerating price declines. Consumer electronic products are technologically different from non-electronic goods, in that semiconductors are important components. As the price of semiconductors has dropped rapidly, the falling production costs can be rapidly incorporated to the price of consumer electronic goods. Furthermore, most of the recently introduced consumer electronic products have network externalities, and many products with network externalities require complementary products. A complementary product becomes more readily or cheaply available as more people have the main product. One major difference between previous studies and this study is that the former focuses only on the factors that operate directly on the speed of adoption, while this study incorporated factors that work through price changes as well as the factors that work directly on the speed of adoption.
        4,000원
        125.
        2015.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In recent years, flame synthesis has absorbed a great deal of attention as a combustion method for the production of metal oxide nanoparticles, carbon nanotubes, and other related carbon nanostructures, over the existing conventional methods. Flame synthesis is an energyefficient, scalable, cost-effective, rapid and continuous process, where flame provides the necessary chemical species for the nucleation of carbon structures (feed stock or precursor) and the energy for the production of carbon nanostructures. The production yield can be optimized by altering various parameters such as fuel profile, equivalence ratio, catalyst chemistry and structure, burner configuration and residence time. In the present report, diffusion and premixed flame synthesis methods are reviewed to develop a better understanding of factors affecting the morphology, positioning, purity, uniformity and scalability for the development of carbon nanotubes along with their correlated carbonaceous derivative nanostructures..
        4,000원
        126.
        2014.12 KCI 등재 구독 인증기관·개인회원 무료
        목 적 : 확산강조영상은 골격근 손상이 있을 때 조기에 근육의 신호강도 변화를 알 수 있고 양성과 악성 척추 압박골절의 감별 진단에 유용하다고 보고 되고 있지만 질환에 따른 현성확산계수(Apparent Diffusion Coefficient:ADC)의 연구는 많이 보고 되고 있지 않다. 이에 단순 압박 골절과 전이성 척추암이 b value에 따라서 어떠한 변화가 있는지를 알아보고자 본원에서 시행하고 있는 b value 0 400,1400(s/mm²)를 이용하여 각각의 Signal Intensity의 표준화된 값과 물 분자의 확산 정도를 수치화 하는 ADC, 그리고 신호대 잡음비(Signal to Noise:SNR)를 비교하였다. 대상 및 방법 : 2013년 3월부터 2013년 12월까지 MR판독에서 단순복합골절과 전이성 척추암을 의심하는 환자 중 전자의무기록상 확정된 환자로 두 질환 별로 11명씩 총 22명을 대상으로 하였고 평균연령은 각 질환 별로71.2, 56.6세다. 검사장비는 1.5 Tesla Achieva MRI시스템과 Syn-Spine Coil를 사용하였다. Sequence는 DWI SE-EPI Sagittal(Diffusion Weighted Imaging Spin Echo-Echo Planar Imaging Sagittal)영상으로 TR(ms) 1988, TE(ms) 68, FOV(mm) 300, Mat. 128×128, Thk.(mm) 4, Gap(mm) 0.4, Slice 13, b-factor(s/mm²) 0,400,1400의 Parameter를 이용하였다. 데이터 분석은 확산강조영상 b value 0(s/mm²) 영상에서 SI(Signal Intensity)가 높은 질환 부위에 ROI(Region of Interest)를 잡았고 정상부위는 질환부위 바로 위에서 측정하였다. MRIcro Program을 사용하여 b-value 0, 400, 1400(s/mm²)의 영상으로 각각의 SI를 구하였고 b-value의 각 영상을 가지고 Metlab Software를 이용하여 ADC map을 구하여 이 영상을 가지고 MRIcro Program을 사용해 동일한 위치에 ROI를 적용하여 ADC를 구하였다. 데이터 분석은 첫째 두 질환 별로 b value 0 기준으로 400, 1400(s/mm²)의 SI를 표준화하여 비교 분석하였고(SI400/SI0, SI400/SI0) 둘째 두 질환의 정상부위와 질환부위의 ADC와 SNR를 비교 분석하였다. 통계의 유의성은 MS Excel 의 T-Test를 이용하였다. 결 과 : 단순압박골절의 표준화 값(SI400/SI0, SI400/SI0)은 0.47±0.04, 0.23±0.03이고 전이성 척추암의 표준화 값 (SI400/SI0, SI400/SI0)은 0.57±0.07, 0.32±0.08로 나왔고 두 질환 별 표준화 값은 통계적으로 유의하게 나왔다 (p<0.05). 단순압박골절 질환부위의 b value 400(s/mm²)과1400(s/mm²)에 대한 ADC(mm²/s)는 1.70±0.16, 0.93±0.28이고 전이성 척추암은 1.24±0.21, 0.80±0.15로 측정되었다. 두 질환에서 b value 400(s/mm²)에 대한 ADC(mm²/s)는 통계적으로 유의하게 나왔으나(p<0.05) b value 1400(s/mm²)에 대한 ADC(mm²/s)는 유의하지 않았다(p>0.05). 단순압박골절과 전이성 척추암 질환부위의 b value(0/400/1400(s/mm²) 에 따른 SNR 보면 65.61±2.61/36.32±2.92/20.22±2.16, 48.40±2.72/39.27±7.51/23.02±6.25로 측정되었다. 결 론 : 위 연구는 본원에서 검사하고 있는 b value 0,400,1400(s/mm²)을 이용하여 연구를 하였으며 b value 400(s/mm²)에서 두 질환에서의 표준화 된 값과 현성확산계수의 확연한 차이가 있었다. 결론적으로 일반적인 척추 자기공명영상 검사와 병행하여 확산강조영상의 현성확산계수를 가지고 다양한 척추 질환에 적용시킨다면 보다 정확한 진단에 도움이 될 거라 사료된다. 본 연구의 제한점으로 다양한 b value를 적용하지 못했고 성별, 나이, 각 질환의 병기 및 시기, 전이암의 최초 발병 부위를 정립하지 않았으며 측정 부위를 조영제를 사용한 영상이 아닌 단순히 b value 0(s/mm²)에서 고신호 강도가 나오는 곳의 데이터로 결론을 도출한 점은 앞으로 보완해야 할 것이다.
        127.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 생활주변에서 오존수를 쉽게 활용할 수 있도록 오존수 발생장치의 활용성을 증가시키고 한 동작으로 작동하는 시스템을 개발하고자 한다. 더 나아가 올리브 오일과 오존과 반응시켜 제조하는 기술에 적용하고자 한다. 기존의 경우 대부분이 오존수 시스템이 아닌 오존발생기 위주의 제품이 많다. 오존수기의 경우 펌프로 강제 흡입시키는 일반압력 방식으로 오존가스 누출 위험요소가 내포 되어 있으나, 본 과제의 경우 인젝터를 이용하여 물의 유입여부에 따른 오존의 발생과 흡입을 제한하고 있어 기존 제품의 오존 누출에 의한 위험을 최소화하였다. 인젝터 방식의 단점에도 불구하고 미생물 살균능을 유지하는 것으로 본 연구에서 사용된 인젝터 방식 오존수 제조 장치의 효용성을 알 수 있었다.
        4,000원
        128.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 한국 남해 연안에서 하계에 상습적으로 발생하는 유해적조생물의 이동과 확산에 관하여 파악하는 것이다. 먼저 3차원 해수유동모델(POM)을 이용하여 조석의 효과, 수온·염분, 바람 효과 및 쓰시마난류를 고려한 잔차류를 계산하였다. 잔차류에 의해 부유이동하는 적조생물의 시간에 따른 공간적인 분포를 파악하기 위하여 국립수산과학원의 적조속보 자료를 이용하여 한국 남해안에서 유해적조의 최다 발생한 3개 지역 가막만(Case 1), 미조연안(Case 2), 미륵도연안(Case 3)을 선정하여 적조발생을 유형별로 수치실험을 하였다. 가막만 남부해역에서 적조가 발생한 경우(Case 1)는 발생지점으로부터 서쪽에 위치한 나로도주변해역과 여자만으로 주로 이동 확산하였다. 미조연안에서 적조가 발생한 경우(Case 2)는 발생해역의 북동측에 위치한 해역으로 입자들이 주로 이동하는 것으로 나타났다. 그리고 미륵도 주변해역에서 입자가 발생한 경우(Case 3)는 욕지도주변해역과 자란만-사량도 주변해역에서 가장 많이 분포하였다. 특히 Case 3의 경우 확산된 입자가 연구 해역의 남동쪽에서 북동향하여 진행하는 쓰시마 난류의 영향을 받아 거제도 남부와 동부해역에 분포하는 현상을 볼 수 있다.
        4,000원
        129.
        2014.07 구독 인증기관 무료, 개인회원 유료
        All aspects of individual consumer as well as situational affecting on decisions are influenced by the social and cultural structure in which the consumer is embedded. Recently, there has been a growing worldwide phenomenon whereby tourists visit an attraction or destination as a result of that place being portrayed or represented in the popular cultural forms of the media that are not directly related with tourism promotion or marketing. A number of studies have suggested that such portrayals and features of mass media can act as powerful forces that stimulate tourism demand (Beeton, 2001). Representations and images of tourist destinations constructed by popular cultural forms of media such as films, television and literature play a significant role in influencing people’s holiday decision-making process (Iwashita, 2006). Where trade in images, expectations, dreams, and fantasies are made in tourism (Selwyn, 1996), those media representations and images of tourist destinations play a significant role in influencing people’s decision-making process. The tourism industry also is increasing appliance of images that are drawn from popular culture associated with places to promote tourist destinations and to distinguish themselves from each other. While these researches contribute to the understanding of the influence of pop culture on tourism phenomena, only few studies have investigated on the actual linkage between the pop culture and tourism perceptions/behaviors. The reason why pop culture involvement can be related to the actual intention to visit is due to the fandom created relating to the pop culture. The notion of fandom has been put forward in order to understand the link in between the pop culture and the mass audience in diverse realms (Couldry, 2007). Fandom in recent years have been understood to dismiss the negative view of pathological and the stem for alienating qualities of modern society, and accepted as a phenomena widely spread in post-industrial societies (Jenson, 1992). It is then when transitional moment takes place, in the head and heart of the fan or tourist, that the fascination begins which provides the motivation to visit the locations (Reijnders, 2011). With such cultural industries in modern society constantly produce countless contents that can be utilized as objects of fandom, resulting in actual visit to a place associated with a specific destination serving as an effective strategy for building popular cultural capital in modern society. It was therefore decided to investigate this phenomenon in more depth through empirical research to investigate how and to what extent popular cultural forms of the media (those not directly associated with tourism and destination marketing) have an effect on international tourism, and future, to identify what roles they play in influencing tourists from emerging market in terms of their travel destination image and their perception about places to visit within the chosen destination. The phenomenon in this study focuses on the Korean wave, so called Hallyu, as it is one of the pop culture phenomenon that has gained much recognition across not only within Asian countries but also recently in Western countries via pop songs, soap operas, movies, and other forms of mass media entertainment. In this study, diffusion model suggested by Rogers (1995) was used. The diffusion of Rogers’s innovation framework is proving flexible enough to conceptualize many kinds of social change, including change through processes of public dialogue and civic participation, change within organizations, as well as change through public agenda setting and media effects. Many studies have incorporated diffusion theory to explain such cultural phenomenon to gain more enrich result, however, no other studies have looked into the degree of diffusion stage in a macro level according to the regions. However, to obtain the overall view of the diffusion of such pop culture, it is needed to see the diffusion process proceeding globally as even the same fandom may differ in characteristics based on not only the diffusion stage but also its distinctive characteristics of social system. As a result, according to the diffusion stage of Hallyu, it is expected to differ in formation and perception on destination image. Previous studies identify destination image into cognition and affect which are two conceptually different, yet highly correlated components (Lee, 2008). The cognitive component leading to some internally accepted attributes, a more or less derived from factual information. On the other hand, the affective component relates to a diffusive feeling, which can become important when a decision to travel is actually considered (Russel, 1980). Such image constructed by tourists contains an individual or group perception of a particular place (Fakeye and Crompton 1991). It is expected that the image construction will vary according to the stage of the diffusion. This study incorporates diffusion theory to develop a better understanding of the diffusion process and the current situation of the Korean Wave globally to see whether such diffusion process varies according to region. Then, the effect of such difference in diffusion stages on the intention to visit the destination country was investigated. Thus, preliminary research was conducted first to see the Korean Wave phenomenon globally. In order to analyze the diffusion stage thoroughly, three regions of Asia, America, and Europe were selected. According to the diffusion degree of the Korean wave, seven representative countries were elected regarded to the regions. Along with literatures, in-depth interviews were conducted. The semi-structured form with an interview guide method was presented with reflexive interviewing techniques in order to ensure comprehensiveness (Athos & Gabarro, 1978). Then, a survey was conducted to examine the effect of pop culture involvement on formation and perception of destination image in China and Russia. Choice of countries is not only resulting from recognition as the potential future powerhouse in industry, but because it is the two countries take place as one of the highest increase in the number of tourists visiting Korea recently (KCTI, 2013). In addition, most importantly, China represents to be in the highest stage of diffusion of Korean pop culture, and Russia as one of the lowest. Additionally, the moderating effect of travel intention and travel behavior was preceded. From this, it aims to provide deeper understanding implications for targeting tourists. The hypotheses were tested with a data set developed from field survey using only online survey. Of the 265 samples collected, 8 were returned incomplete. An additional 18 samples were deleted for further analysis, as the answers were unusable. In total 239 samples – 120 and 119 samples from China and Russia respectively – were subjected for final analysis. The result in Study 1 revealed some commonalities and differences among regions. Overall, uniqueness was what made people first be interested. It was mostly pursued by young women yet those who are sometimes extremist. Thus, being open-minded to other cultures was found to be important when accepting other cultures. Moreover, it revealed that it impacts on national image to be more positive as it replaces the negative image related to war and North Korea. However, despite some commonalities, distinctive differences were disclosed among regions, especially between Asian countries and Western countries. In terms of Asia, it was found that cultural similarities have influenced the early acceptance of Korean pop culture. It has been spread since 1997, through television mostly with sensuous contents that were unique in other countries. The contents were mostly appealing to women as the characters shown in soap opera were different to others. This is very different to Europe of America where the diffusion starting in the mid 2000 through the Internet. Uniqueness captured consumers, yet in a different way from Asian countries. The easy going and entertaining aspect was the appealing factor, with word of mouth and human power was what influenced in introduction of Korean pop culture. In addition, those who were into Japanese culture were easily approached to Korean pop culture. The diffusion stage was considered to be less than 10%, with very young women interested with comparison with Asia where it was about 70%. Moreover, it was found that Asian consumers are interested in Korean brand products, such as cosmetics and clothing, and Western consumers are more interested in culture and food. Then, on the survey proceeded where China and Russia was chosen based on the preliminary qualitative research as a two different stage of diffusion according regions/countries, t-test provided evidence to support the claim that depending the diffusion stage of pop culture, the effect on formation and perception of destination image differs. A significant differences were obtained in pop culture involvement, destination image (cognitive and affective), and on visit intention. Based on the t-test statistics for Korean pop culture involvement (t = 8.491, p < .000), the cognitive image (t = -3.341, p < .001), the affective image (t = 2.050, p < .05), and visit intention (t = 2.072, p < .05) were significant. Thus, when highly involved in Korean pop culture, rather than cognitive image, consumers are more likely to be involved with affective image which relates to the actual visit intention. The results corroborated several hypothesized relationships, popular culture involvement in accordance to nation affect the destination image and perception. When more highly involved, more positively it relates to affective image and the visitation intention. The findings reported in this study have managerial implications. One is that as the relation differs according to the diffusion stage, spreading pop culture may not yield visible output instantly, yet as it relates to the actual visitation intention, international pop culture activities should be supported. Second, as shown from the diffusion process globally, distinctive characteristics of each culture should be considered more when spreading such sub-culture. Lastly, therefore, it can be suggested, that according to the countries, different approach should be made in order to induce tourist from other countries. However, this study focuses more on the macro level of the phenomenon. Therefore, future research is needed to provide more evidence on the micro level and more in-depth research. In addition, this study precedes empirical study only in China and Russia. Therefore, more diverse countries should be explored and compared.
        4,000원
        130.
        2014.02 구독 인증기관 무료, 개인회원 유료
        In this study, we aim at the workplace which is report target about person who emits much food waste, apartment house and detached house. We respectively selected 3 places in this study. Density of average complex bad odor which is generated in storage container of food waste appears high in order of workplace(2,523.8 OU/m3), apartment house(2,135.7 OU/m3) and detached house(1,556.5 OU/m3). And then, it doesn’t seem like big difference. However, these appear degree of bad smell intensity which is more than 3. Meanwhile, bad smell intensity about 3 same occurrence sources which are classified (three places which are respectively workplace, apartment house and detached house)appears big difference. Therefore, we must completely follow the meter-rate system of food waste to reduce the bad smell intensity of storage container of food waste. Also, we must use verified products in order that quality of exclusive storage container prohibits leakage of bad odor. And then, we must periodically clean the storage container and sterilize it. In addition, when we discharge food waste, we must decrease moisture content to squeeze included water. Also, we must make an effort to reduce storage period , as much as possible. And then, it is necessary to prepare countermeasure about this.
        4,000원
        132.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 배터리 전극 해석을 위한 응력-확산 완전 연계 멀티스케일 해석기법을 고안하였다. 제안된 방법에서는 먼저 리튬농도에 따른 확산계수 및 기계적 물성을 계산하였다. 이를 고려하여 확산에 의한 응력뿐만 아니라 응력에 의한 확산거동 변화까지 모두 고려한 응력-확산 완전연계 연속체 모델을 유한요소 기반으로 구성하였다. 이를 통해 실리콘 나노와이어 음극의 충/방전 전산 모사를 수행하였다. 이러한 해석결과를 통하여 기존의 확산에 의한 응력 연속체 모델보다 더 실제와 가까운 해석결과를 제안된 방법이 보여줌을 확인할 수 있었다.
        4,000원
        135.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, applied areas of nonferrous materials have been expanded in terms of efficiency of materials used and cost reduction. And, in accordance with compactness and accuracy of parts, the need of joining of dissimilar materials is raised. Accordingly, this study aimed at finding out the optimal welding current value(6.3~6.5kA) considering tensile strength, fracture test and welding residue after joining with various welding conditions by means of copper pipe(Φ7.0 × t0.5) and aluminium pipe(Φ7.0 × t0.7) using an eutectic diffusion bonding machine.
        4,000원
        136.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we fabricated Nd2Fe14B hard magnetic powders with various sizes via spray drying combined with reduction-diffusion process. Spray drying is widely used to produce nearly spherical particles that are relatively homogeneous. Thus, the precursor particles were prepared by spray drying using the aqueous solution containing Nd salts, Fe salts and boric acid with the target stoichiometric composition of Nd2Fe14B. The mean particle sizes of the spray-dried powders are in the range from one to seven micrometer, which are adjusted by controlling the concentra- tions of precursor solutions. After debinding the as-prepared precursor particles, ball milling was also conducted to con- trol the particle sizes of Nd-Fe-B oxide powders. The resulting particles with different sizes were subjected to subsequent treatments including hydrogen reduction, Ca reduction and washing for CaO removal. The size effect of Nd-Fe-B oxide particles on the formation of Nd2Fe14B phase and magnetic properties was investigated.
        4,200원
        137.
        2013.08 구독 인증기관 무료, 개인회원 유료
        This paper investigates the downwash effect of a rooftop structure (RTS) representing a typical RTS with jet diffusion. The effect of rooftop structure height on the severity of the downwash effect is assessed. As a result, design guidance provided for determining structure height required to avoid the downwash effect.
        3,000원
        138.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A novel route to prepare Nd-Fe-B magnetic particles by utilizing both spray drying and reduction/diffu- sion processes was investigated in this study. Precursors were prepared by spray drying method using the aqueous solu- tions containing Nd salt, Fe salt and boric acid with stoichiometric ratios. Precursor particles could be obtained with various sizes from 2 to 10 µm by controlling concentrations of the solutions and the average size of 2 µm of precursors were selected for further steps. After heat treatment of precursors in air, Nd and Fe oxides were formed through desalt- ing procedure, followed by reduction processes in Hydrogen (H2) atmosphere and with Calcium (Ca) granules in Argon (Ar) successively. Moreover, diffusion between Nd and Fe occurred during Ca reduction and Nd2Fe14B particles were formed. With Ca amount added to particles after H2 reduction, intrinsic coercivity was changed from 1 to 10 kOe. In order to remove and leach CaO and residual Ca, de-ionized water and dilute acid were used. Acidic solutions were more effective to eliminate impurities, but Fe and Nd were dissolved out from the particles. Finally, Nd2Fe14B magnetic particles were synthesized after washing in de-ionized water with a mean size of 2 µm and their maximum energy prod- uct showed 9.23 MGOe.
        4,000원
        139.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present study, we systematically investigated the effect of Mn addition on nitrogenation behavior and magnetic properties of Sm-Fe powders produced by reduction-diffusion process. Alloy powders with only single phase were successfully produced by the reduction-diffusion process. The coercivity of powder rapidly increased during nitrogenation and reached the maximum of 637 Oe after 16 hours. After further nitrogenation, it decreased. In contrast, the coercivity of powder gradually increased during nitrogenation for 24 hours. The coercivity of powder was higher than that of powder at the same condition of nitrogenation. It was considered that the Mn addition facilitates the nitrogenation of powder and enhances the coercivity.
        4,000원
        140.
        2013.02 구독 인증기관 무료, 개인회원 유료
        In this paper, a three dimensional numerical analysis tool was applied to study the PEMFC performance characteristics. The porosity and electrical conductivity of GDL and CL as well as the relative humidity of anode and cathode channel gas were selected as simulation parameters. As the porosity of GDL and CL increases, current density and temperature increase because reactant gases diffuse well. As the electrical conductivity of GDL and CL increases, current density and temperature increase due to increased electron transfer rate. As anode relative humidity increases, current density and temperature increase. Unlike anode, current density and temperature increase when cathode relative humidity increases from 0 percent to 60 percent. Then current density and temperature decrease when cathode relative humidity increases from 60 percent to 100 percent.
        4,000원